TWI524546B - Solar cell, solar cell module, printing screen unit, and printing screen - Google Patents

Description

Solar cell, solar cell module, printing screen group And screen

The invention relates to a solar cell, a module thereof, a screen and a screen plate group for printing, in particular to a twin crystal solar cell and a module thereof, and a screen and a net for screen printing to form an electrode of the battery. Group.

Referring to Fig. 1, a known twinned solar cell mainly comprises: a photoelectric conversion substrate 91 for converting light energy into electrical energy, and a front electrode 92 and a back electrode (not shown) for conducting current. The front electrode 92 includes a plurality of bus bar electrodes 921, and a plurality of laterally connected bus electrodes 921 and has an elongated finger electrode 922. In the manufacturing, the front electrode 92 can be coated with a conductive paste by screen printing, and the conductive paste can be solidified by a sintering process to form the bus electrode 921 and the plurality of finger electrodes 922.

When the solar cell is manufactured, a plurality of batteries are packaged into a battery module, and the package must be connected to adjacent batteries through a plurality of ribbons, not shown, along which one of the ribbons is connected. The bus electrode 921 on the front of the battery is extended and connected to the back of the other battery The electrodes are connected to join a plurality of batteries in series. However, since the plurality of finger electrodes 922 and the bus electrodes 921 of the battery are formed by two screen printing steps, the joints 923 of the plurality of finger electrodes 922 and the bus electrodes 921 may overlap due to the two screen printing pastes. The height is high, which makes the soldering wire lead easy to bridge when it is soldered, which is not conducive to the soldering of the soldering wire, resulting in the local line segment of the soldering wire being supported by the connecting portion 923 and between the plurality of collecting electrodes 921. The gap is formed and the bonding is not easy, so that the soldering wire and the bus electrode 921 cannot be smoothly joined, and the welding bonding force between the two becomes small, thereby causing a problem that the welding bonding strength is insufficient, which will affect product reliability.

Accordingly, it is an object of the present invention to provide a solar cell and a module thereof capable of improving the solder joint strength of a ribbon conductor, and a screen set and screen for screen printing to form an electrode of the battery.

Therefore, the solar cell of the present invention comprises: a substrate having a light receiving surface, at least one first electrode, and a plurality of second electrodes. The first electrode is located on the light receiving surface and extends along a first direction. The plurality of second electrodes are located on the light receiving surface and are connected to the first electrode, and the second electrodes are arranged in parallel at intervals. And the connection between the first electrode and the at least one of the second electrodes has at least one recess, and wherein at least one of the second electrodes has an extended electrode portion, the extended electrode portion faces the recess The direction extends and contacts the recess.

The solar cell module of the present invention comprises: a first plate and a second plate disposed oppositely, a plurality of solar cells as described above and arranged between the first plate and the second plate, and a package. The packaging material Located between the first plate and the second plate and wrapped around the plurality of solar cells.

The screen set for printing of the present invention is used for printing to form as described above The first electrode and the second electrode of the solar cell, the printing screen set comprises: a first screen and a second screen.

The first screen is used for printing to form the first electrode and includes a first mesh, and a first barrier layer fixed on the first mesh, the first barrier layer includes a first linear opening extending in the first direction, and at least one is located in the first line a blocking unit in the opening. The second screen is used for printing to form the plurality of second electrodes, and includes a second mesh, and a second barrier layer fixed on the second mesh, the second barrier layer comprises a plurality of parallel arrays a second linear opening, and at least one extended opening unit connected to one end of at least one of the plurality of second linear openings, the extended opening unit corresponding to the blocking unit of the first screen and used for printing The extended electrode portion is formed.

The invention also provides a screen for printing to form as described above a first electrode of the solar cell, the screen comprising: a first mesh, and a first barrier layer fixed to the first mesh, the first barrier layer including a first extending in the first direction a linear opening and at least one blocking unit located in the first linear opening.

The invention also provides another screen for printing to form as above The second electrode of the solar cell, the screen comprises: a second mesh, and a second barrier layer fixed on the second mesh, the second barrier layer comprising a plurality of second lines arranged in parallel An opening, and at least one connected to the number An extended opening unit at one end of at least one of the second linear openings for forming the extended electrode portion, the extended opening unit including a plurality of extending openings arranged in parallel.

The effect of the invention is that the recess is provided by the first electrode, The extension electrode portion of the second electrode is extendable to prevent the electrode material at the junction of the first electrode and the second electrode from overlapping. Or even if the first electrode and the second electrode partially overlap, the electrode paste can be bleed by the concave portion provided by the first electrode, so that the junction between the last first electrode and the second electrode can maintain a relatively flat surface, so The connection between the first electrode and the second electrode of the present invention is relatively flat, so that a solder ribbon can be firmly welded to the first electrode to improve the solder joint strength of the solder ribbon.

1‧‧‧ first plate

2‧‧‧Second plate

3‧‧‧Solar battery

31‧‧‧Substrate

311‧‧‧Stained surface

312‧‧‧ back

313‧‧ ‧ emitter layer

314‧‧‧Anti-reflective layer

32‧‧‧Back electrode

33‧‧‧First electrode

331‧‧‧ side

332‧‧‧ recess

333‧‧‧ recessed area

34‧‧‧second electrode

341‧‧‧Extended electrode section

342‧‧‧ branch electrode segment

4‧‧‧Package

5‧‧‧welding wire

61‧‧‧First direction

62‧‧‧second direction

7‧‧‧First Screen

71‧‧‧First mesh

711‧‧‧ network cable

72‧‧‧ first barrier

720‧‧‧ Screen printing structure

721‧‧‧First line opening

722‧‧‧Open side

723‧‧‧block unit

724‧‧‧Block section

8‧‧‧ Second Screen

81‧‧‧second mesh

811‧‧‧ network cable

82‧‧‧second barrier

821‧‧‧Second wire opening

822‧‧‧Extended opening unit

823‧‧‧Extended opening

W1, w2‧‧‧ width

D‧‧‧ length

Other features and effects of the present invention will be apparent from the following description of the drawings, wherein: FIG. 1 is a front view of a known solar cell; FIG. 2 is a preferred embodiment of the solar cell module of the present invention. 3 is a front view of a solar cell of the preferred embodiment; FIG. 4 is a cross-sectional view taken along line AA of FIG. 3; and FIG. 5 is an enlarged view of a circled area of FIG. Figure 6 is a front elevational view of a first barrier layer of a first screen of a preferred embodiment of the printing screen set of the present invention; Figure 7 is a partial enlarged view of Figure 6; Figure 8 is the first network A partial cross-sectional view of the version, the cross-sectional position of which Figure 7 is a front elevational view of a second barrier layer of a second screen of the preferred embodiment of the printing screen set; Figure 10 is a partial enlarged view of Figure 9; 11 is a partial cross-sectional view of the second screen, the cross-sectional position of which is shown by the CC line of FIG.

Referring to FIGS. 2 and 3, a preferred embodiment of the solar cell module of the present invention comprises: a first plate 1 and a second plate 2 disposed opposite each other, and a plurality of arrays arranged on the first plate 1 and the first a solar cell 3 between two sheets 2, at least one package 4 between the first sheet 1 and the second sheet 2 and wrapped around the plurality of solar cells 3, and a plurality of strips for serially connecting the plurality of A ribbon 5 of the solar cell 3.

The first plate 1 and the second plate 2 are not particularly limited in implementation, and a glass or plastic plate may be used, and the plate on one side of the light receiving surface of the battery must be permeable; if it is a double-sided light receiving battery, Both the first sheet 1 and the second sheet 2 must be permeable to light. The material of the encapsulant 4 is, for example, a light transmissive ethylene vinyl acetate copolymer (EVA), or other related materials that can be used for solar cell module packaging.

The structures of the plurality of solar cells 3 are the same, and only one of them will be described below as an example. However, it is necessary that several batteries in the same module are not identical in structure.

Referring to FIGS. 3, 4, and 5, the solar cell 3 includes a substrate 31, a back electrode 32, a plurality of first electrodes 33, and a plurality of second electrodes. Extreme 34.

The substrate 31 has an opposite light receiving surface 311 and a back surface 312, an emitter layer 313 is disposed on the inner side of the light receiving surface 311, and an anti-reflection layer 314 is selectively disposed on the emitter layer 313. The substrate 31 is, for example, a semiconductor germanium substrate, and one of the substrate 31 and the emitter layer 313 is an n-type semiconductor, and the other is a p-type semiconductor, thereby forming a p-n junction. The material of the anti-reflective layer 314, such as tantalum nitride, can be used to reduce light reflection to increase the amount of light incident.

The back electrode 32 is located on the back surface 312 of the substrate 31. For cooperating with the first electrode 33 and the second electrode 34, the electric energy of the battery is output to the outside.

The number of the first electrodes 33 of this embodiment is three but not limited The first electrodes 33 are located on the light receiving surface 311 and extend along a first direction 61. The plurality of first electrodes 33 are in a second direction different from the first direction 61. 62 intervals. The first direction 61 of the present embodiment is perpendicular to the second direction 62, but is not limited thereto. Each of the first electrodes 33 of the present embodiment has two side edges 331 which are arranged along the second direction 62 and extend along the first direction 61, and a plurality of concave portions 332 respectively located on the two side edges 331. The plurality of recesses 332 are respectively located at the junction of the first electrode 33 and each of the second electrodes 34. The plurality of recesses 332 refer to a portion where the first electrode material is not formed between the two side edges 331 of the first electrode 33. In the embodiment, each recess 332 is from one side 331 toward the other. The direction of the side 331 is recessed, and each recess 332 of the embodiment has a plurality of intervals along the first direction 61, and all along The second direction 62 is a recessed area 333 that extends parallel to each other.

The plurality of second electrodes 34 are disposed on the light receiving surface 311 and connected to the plurality of first electrodes 33. The plurality of second electrodes 34 can pass through the anti-reflective layer 314 to contact the emitter layer 313. The plurality of second electrodes 34 extend along the second direction 62, and a portion of the second electrode 34 simultaneously connects the two first electrodes 33, and a portion of the second electrodes 34 are connected to only one of the first electrodes 33. Among the plurality of second electrodes 34, the plurality of second electrodes 34 connected to the same side 331 of the same first electrode 33 are parallel to each other, and are arranged along the first direction 61, and each of the second electrodes 34 has An extended electrode portion 341 located at a junction with the first electrode 33 and extending into the first electrode 33. The extending electrode portions 341 of the plurality of second electrodes 34 extend toward the plurality of concave portions 332 of the plurality of first electrodes 33 and extend into contact, thereby causing the plurality of second electrodes 34 and the plurality of first electrodes 33 Form a good connection. Each of the plurality of second electrodes 34 includes a plurality of branch electrode segments 342 that are spaced apart from each other in the first direction 61 and are parallel to each other. The plurality of branch electrode segments 342 can respectively extend into the plurality of recesses of the recess 332 connected thereto. At least some of the regions 333, whereby the connection portion between each of the second electrodes 34 and the first electrode 33 is formed into a structure similar to the finger-like crossover, and the second electrode 34 and the first electrode are further raised. The connection area between 33 and the connection stability.

It should be noted that the number of the first electrodes 33 of the present invention is not limited to three, for example, two or one, and the two first electrodes 33 located at the leftmost and the rightmost sides are not limited to the two sides 331 thereof. The plurality of second electrodes 34 are connected, or only one side 331 is connected to the plurality of second electrodes The electrode 34 is sufficient. Each of the recesses 332 is not necessary to provide the plurality of recessed regions 333. Each of the recesses 332 may have only one recessed area 333. In addition, only the recessed portions 332 may be disposed in at least one of the recessed portions 332. In the plurality of second electrodes 34, the plurality of branch electrode segments 342 may be disposed only on the extended electrode portions 341 of at least one of the second electrodes 34 to extend into the plurality of recess regions 333, respectively. The number of the branch electrode segments 342 of each of the second electrodes 34 of the present embodiment is different from the number of the recessed regions 333 of the recesses 332 connected thereto, so that the plurality of branch electrode segments 342 of each second electrode 34 are only filled in the number Some of the recessed regions 333; however, the number of the branch electrode segments 342 may be the same as the number of the recessed regions 333 so that each recessed region 333 can be filled by a branch electrode segment 342. In addition, the present invention may also be designed as follows, the first electrode 33 and the at least one of the second electrodes 34 have at least one recess 332 at the junction of the second electrodes 34, and at least one of the second electrodes The 34 has an extended electrode portion 341 that extends in the direction of the recess 332 and contacts the recess 332.

Preferably, each of the extended electrode portions 341 has a width w1 of 60 to 80 μm and a length d of less than 200 μm . The width w1 of the extended electrode portion 341 refers to the length of the extended electrode portion 341 in the first direction 61, and refers to the distance between the opposite sides of the extended electrode portion 341 in the first direction 61. The length d of the extended electrode portion 341 is the length of the portion of the second electrode 34 that protrudes into the first electrode 33 in the second direction 62. The width w1 and the length d of the extending electrode portion 341 are designed such that the portion of the second electrode 34 that protrudes into the first electrode 33 is sufficiently large, so that the second electrode 34 and the first electrode 33 can be firmly connected. The length of the second electrode 34 extending into the first electrode 33 does not need to be too long, so that the length d of the extended electrode portion 341 is preferably limited to less than 200 μm.

Preferably, the plurality of branch electrodes of the extended electrode portion 341 The width w2 of the segment 342 is 20 to 30 μm. The width w2 of each branch electrode segment 342 refers to the length of the branch electrode segment 342 in the first direction 61. The width of the branch electrode segments 342 is designed such that the respective branch electrode segments 342 and the first electrode 33 can be firmly connected.

Referring to Figures 2, 3 and 5, the present invention is provided by the first electrode 33. The plurality of concave portions 332 are formed, and the material of the first electrode 33 is not formed at the portion where the plurality of concave portions 332 are located. Therefore, when the second electrode 34 is not formed, the plurality of concave portions 332 are hollowed out, and the plurality of concave portions 332 are vacant. The extending electrode portions 341 of the plurality of second electrodes 34 are inserted into the plurality of recesses 332, and the materials of the second electrodes 34 are mainly filled in, so that the plurality of first electrodes 33 and the plurality of second portions can be avoided. The problem that the electrode materials at the junction of the electrodes 34 overlap; or the recessed portion 332 provided by the first electrode 33 allows the electrode paste to be infiltrated even when the first electrode 33 and the second electrode 34 partially overlap, so that the last first electrode A relatively flat surface can still be maintained at the junction of the 33 and the second electrode 34. Therefore, the junction between the first electrode 33 and the second electrode 34 of the present invention is relatively flat, and the thickness of the joint is substantially the same as the thickness of the first electrode 33 itself, so that the ribbon wire 5 can be firmly connected to the plurality of An electrode 33 is welded and bonded, so that the welding bonding strength of the ribbon conductor 5 can be improved, and the welding bonding strength of the ribbon conductor 5 can be improved due to the excessive overlap of the material at the junction of the bus electrode and the finger electrode. The problem.

As can also be seen from the above description, the present invention does not need to define the recess 332. The shape and the shape of the extension electrode portion 341 are similar to the design in which the first electrode 33 does not have the first electrode material in the first electrode 33, and the first electrode 33 and the second electrode 34 are prevented from overlapping. , are the scope of protection of the invention.

Referring to Figures 5, 6, and 9, one of the printing screen sets of the present invention is compared. A preferred embodiment is for printing a first electrode 33 and a second electrode 34 of the solar cell 3 as described above. The printing screen set comprises: a first screen 7 and a second screen 8.

Referring to Figures 3, 6, 7, and 8, the first screen 7 is used for printing. The plurality of first electrodes 33 are formed and include a first mesh 71 and a first barrier layer 72 fixed to the first mesh 71. The first mesh 71 includes a plurality of interlaced network wires 711. The material of the first barrier layer 72 is a polymer material or a metal. The hole pattern on the first barrier layer 72 corresponds to the shape of the three first electrodes 33. The first barrier layer 72 includes three spaced apart along the second direction 62 and is respectively used to form the three first electrodes. Screen printing structure 720 of 33. Each screen printing structure 720 includes a first linear opening 721 extending along the first direction 61 and arranged in parallel, two opening sides 722 spaced apart and extending along the first direction 61, and a plurality of spaced apart sides and A blocking unit 723 located in the first linear opening 721. In each of the screen printing structures 720, the plurality of blocking units 723 are respectively arranged on the left and right sides of the first linear opening 721, and are respectively connected to the two opening side edges 722. The plurality of blocking units 723 located on the same side of the first linear opening 721 are spaced apart along the first direction 61, and each blocking unit 723 is self-contained. The opening side 722 connected thereto extends along the second direction 62 toward the first linear opening 721, and each of the blocking units 723 includes a plurality of parallel spaced along the first direction 61 and both along the second direction. 62 extended blocking section 724.

Referring to Figures 5, 6, and 7, the net of the first electrode 33 of the battery is performed. In the printing process, an electrode paste for forming the first electrode 33 is coated on the first screen 7, and is scraped by a doctor blade (not shown) to pass the electrode paste through the plurality of electrodes. The first linear opening 721 is applied to the substrate 31 of the battery. Since the first screen 7 is provided with the plurality of barrier units 723, the electrode paste can be blocked, and the first plurality formed by the screen printing is formed. The electrode 33 has the plurality of recesses 332, and the positions and structures of the plurality of recesses 332 correspond to the plurality of barrier units 723, respectively. It should be noted that since the first electrode 33 on the battery is at least one, the screen printing structure 720 of the first screen 7 may be at least one.

Referring to Figures 5, 9, 10, 11, the second screen 8 is used for printing The plurality of second electrodes 34 are formed and include a second mesh 81 and a second barrier layer 82 fixed to the second mesh 81. The second mesh 81 includes a plurality of interlaced network wires 811. The material of the second barrier layer 82 is a polymer material or a metal. The hole pattern on the second barrier layer 82 corresponds to the shape of the plurality of second electrodes 34. The second barrier layer 82 includes a plurality of second linear openings 821 extending in the second direction 62 and arranged in parallel, and a plurality of extended opening units 822 respectively connected to one ends of the plurality of second linear openings 821. Moreover, both ends of the second linear opening 821 in the longitudinal direction are respectively connected to an extended opening unit 822, and a part of the second linear opening 821 has only one end connected to an extended opening unit 822. The plurality of extension opening units 822 are respectively used to print the extension electrode portions 341 forming the plurality of second electrodes 34.

Referring to Figures 7 and 10, the plurality of extended opening units 822 respectively Corresponding to the plurality of blocking units 723 of the first screen 7, each of the extending opening units 822 includes a plurality of extending openings 823 arranged in the first direction 61 and parallel to each other, between any two adjacent extending openings 823 Filled with the material of the second barrier layer 82. The plurality of extended openings 823 of each of the extending openings 822 correspond to a plurality of the plurality of blocking segments 724 of each of the blocking units 723, respectively. In the present embodiment, in the corresponding first blocking unit 723 and the extended opening unit 822, although the number of blocking segments 724 is more than the number of extending openings 823, the number of the two may be equal when implemented.

Referring to Figures 5, 9, and 10, the second electrode 34 of the battery is In the screen printing process, the second screen 8 is first disposed on the substrate 31 of the battery, and the plurality of extended opening units 822 of the second screen 8 respectively correspond to the recesses 332 of the plurality of first electrodes 33. position. Then, an electrode paste for forming the second electrode 34 is coated on the second screen 8 and scraped by a doctor blade to pass the electrode paste through the plurality of second linear openings 821 and the plurality of extensions. The opening unit 822 is applied to the substrate 31, and the electrode paste passing through the plurality of extending openings 822 can be applied to the concave portion 332 of the plurality of first electrodes 33, thereby forming the plurality of screens formed by the screen printing. The two electrodes 34 have the plurality of extended electrode portions 341 which are respectively filled in the concave portions 332.

Referring to Figures 5, 7, and 10, it should be noted that the first electrode 33 printed by the first screen 7 of the present invention is a modified type of bus electrode. (bus bar electrode), and the first screen plate 7 can also be used in conjunction with a screen for printing a finger electrode of a conventional form to fabricate a front electrode of the battery. On the other hand, the second electrode 34 printed by the second screen 8 of the present invention is a modified finger electrode, and the second screen 8 can also be used for the common electrode for printing the conventional form. The screen version is used together. That is, the first halftone 7 of the present invention is not limited to being used in conjunction with the second halftone 8.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

3‧‧‧Solar battery

31‧‧‧Substrate

314‧‧‧Anti-reflective layer

33‧‧‧First electrode

331‧‧‧ side

332‧‧‧ recess

333‧‧‧ recessed area

34‧‧‧second electrode

341‧‧‧Extended electrode section

342‧‧‧ branch electrode segment

61‧‧‧First direction

62‧‧‧second direction

W1, w2‧‧‧ width

D‧‧‧ length

Claims (10)

A solar cell comprising: a substrate having a light receiving surface; at least one first electrode on the light receiving surface and extending along a first direction; and a plurality of second electrodes on the light receiving surface and connecting the first An electrode, wherein the second electrodes are arranged in parallel; and a connection between the first electrode and each of the second electrodes has a recess, and each of the second electrodes has an extended electrode portion, and Each of the extension electrode portions corresponds to one of the recesses; wherein each of the extension electrode portions extends toward and contacts the one of the recesses. The solar cell according to claim 1, wherein the extended electrode portion has a width of 60 to 80 μm and a length of less than 200 μm. The solar cell of claim 2, wherein the recess comprises a plurality of recessed regions arranged in parallel; the extended electrode portion comprises a plurality of branch electrode segments arranged in parallel, and the plurality of branch electrode segments respectively extend into the plurality of Depression area. The solar cell according to claim 3, wherein the plurality of branch electrode segments have a width of 20 to 30 μm. A solar cell module comprising: a first plate and a second plate disposed oppositely; and a plurality of solar cells according to any one of claims 1 to 4, arranged on the first plate and the second plate Between; and An encapsulating material is disposed between the first plate and the second plate and wrapped around the plurality of solar cells. A printing screen set for printing a first electrode and a second electrode of a solar cell according to any one of claims 1 to 4, wherein the printing screen set comprises: a first screen, for Forming the first electrode in printing, and comprising a first mesh, and a first barrier layer fixed on the first mesh, the first barrier layer comprising a first line extending along the first direction An opening, and at least one blocking unit located in the first linear opening; and a second screen for printing to form the plurality of second electrodes, and including a second mesh, and a second fixed to the second a second barrier layer on the mesh, the second barrier layer comprising a plurality of second linear openings arranged in parallel, and at least one extended opening unit connected to one end of at least one of the plurality of second linear openings The extension opening unit corresponds to the barrier unit of the first screen and is used for printing to form the extension electrode portion. The printing screen set according to claim 6, wherein the blocking unit comprises a plurality of blocking segments arranged in parallel; the extended opening unit comprises a plurality of spaced apart openings corresponding to the plurality of blocking segments. The printing screen set according to claim 6, wherein the material of the first barrier layer is a polymer material or a metal, and the material of the second barrier layer is a polymer material or a metal. A screen for printing to form as described in any one of claims 1 to 4. a first electrode of the solar cell, the screen comprising: a first mesh, and a first barrier layer fixed to the first mesh, the first barrier layer including a first extending in the first direction a linear opening and at least one blocking unit located in the first linear opening. A screen for printing a second electrode of the solar cell according to any one of claims 1 to 4, the screen comprising: a second mesh, and a second mesh fixed to the second mesh a second barrier layer comprising a plurality of second linear openings arranged in parallel, and at least one extended opening unit connected to one end of at least one of the plurality of second linear openings, the extended opening unit For forming the extended electrode portion, the extended opening unit includes a plurality of extending openings arranged in parallel.